The broad aims of this proposal are to provide a new magnetic resonance imaging facility at 1.5 Tesla which will enable a diverse group of researchers from chemistry, electrical and nuclear engineering, and veterinary medicine to carry out investigations of clinical relevance. The lack of such a system has meant that promising research in the fields of contrast agent development, dynamic imaging and temperature mapping has essentially been limited to a theoretical level or demonstration of proof-of-concept, rather than being able to show full clinical potential. The specific aims of the projects included within this proposal are: 1) The development of new, targeted contrast agents based on proteinaceous microspheres, which can be used as new abdominal MRI agents, and hold the promise of targeting specific pathologies within the body, 2) The investigation of the effects of ultrasound heating as monitored by MRI, with relevance to the fields of hyperthermia and ultrasound exposimetry, 3) The study of the bioeffects of the static magnetic field, radiofrequency irradiation, and switched magnetic gradients. both alone and in combination with ultrasound treatment, 4) The development of new dynamic imaging techniques for contrast agent enhanced imaging of breast tumors, 5) The design of new paramagnetic contrast agents for MR mammography and hepatic studies, and 6) The design and implementation of new MR techniques for non- invasively measuring temperature changes in vivo.